1. Field of the Invention
This invention relates to a guide roller supporting apparatus provided on the top and bottom of an elevator car for guidance and in particular to a guide roller adapted to decrease the shaking of the car by absorbing lateral displacement forces acting on the car during its up and down movements.
2. Description of the Related Art
Typically, an elevator car is moved up and down while making contact with guide rails provided within a hoistway. These guide rails are subject to displacement and misalignment from an accurate settlement on of the walls of the hoistway caused by a building weight, wind force, and so forth. Furthermore such inaccurate settlement is inevitable because of a non-straightness of the wall of the hoistway.
Such displacement and misalignment of the rail cause the elevator car to be shaken during its up and down movements. The elevator car is increasingly shaken the faster it moves along the rails. Accordingly, guide rollers should have a damping function to decrease the shaking of the elevator car.
FIG. 1 shows a conventional elevator car having two or more guide roller assemblies 54 mounted on the top and bottom of the car, which make contact with guide rails 52. Each of the guide roller assemblies 54 include three rollers contacting with surfaces 52a, 52b and 52c of the guide rail 52(see FIG. 3).
Referring to FIGS. 2 to 4, each of the guide roller supporting apparatuses is mounted on the frame 56 which is secured to the top or bottom of the color. The guide roller supporting apparatus includes a base plate 57 secured to the frame 56 and three brackets 58 mounted on the base plate 57 with a pivotal lever 60 connected at hinge 62 carrying the guide roller 54 mounted for rotation on the bearing axle 64. Three supports 66 are vertically secured to the base plate 57 corresponding to each lever 60, each support having a rod 68 extended through a hole 70 of the lever 60. The rod 68 is provided with a spring 74 between the lever 60 and a stop 72 engaged at the end portion thereof. The spring 74 acts on the lever 60 to resiliently urge the guide roller 58 against the guide rail 52 to support a load transferred to the roller 54. Furthermore, a rod 76 is provided at the support 66 apart from the rod 68, is extended through a hole 78 of the lever 60, and has a stop 80 at an end portion thereof to limit the pivotal movement of the corresponding lever 60 and guide roller 54.
A top plate 82 is secured to the upper ends of the supports 66 and has three dampers 84 in contact with the end of the lever 60 to decrease an oscillation of the lever.
With the conventional guide roller supporting apparatus, when the car 50 moves up and down, each guide roller 54 is subjected to impacts and is pivoted at the hinge 62 because of a misalignment of the rail 52 from its ideal center line. The impacts acting on the guide roller 54 are damped by the spring 74 to decrease the shaking of the car. Furthermore, the excessive pivoting of the guide roller 54 is limited by the stop 80 of the rod 76 to prevent the guide roller from derailing. The dampers 84 also decrease the rebounding of the spring 74.
However, with the conventional guide roller 54, the rod 68 and spring 74 are horizontally provided with the frame 56, whereby the impacts are transferred from the rail 52 through the roller 54 to the elevator car 50. Furthermore, the stop 72 for supporting the spring 74 on the rod 68 is also horizontal to the frame 56, thereby being apt to become loosened.